Scilab Function
Last update : February 2004
interp3d - 3d spline evaluation function
Calling Sequence
- [fp[,dfpdx,dfpdy,dfpdz]]=interp3d(xp,yp,zp,tl,out_mode)
Parameters
-
xp, yp, zp: real vectors or matrices of same size
-
tl: tlist of type "splin3d", defining a 3d tensor spline (called s
in the following)
-
out_mode: (optional) string defining the evaluation of s outside the grid
([xmin,xmax]x[ymin,ymax]x[zmin,zmax])
-
fp: vector or matrix of same format than xp, yp and zp,
elementwise evaluation of s on these points.
-
dfpdx, dfpdy, dfpdz: vectors (or matrices) of same format than xp, yp and zp,
elementwise evaluation of the first derivatives of s on these points.
Description
Given a tlist tl defining a 3d spline function (see splin3d) this function
evaluates s (and ds/dx, ds/dy, ds/dz if needed) at (xp(i),yp(i),zp(i)) :
zp(i) = s(xp(i),yp(i))
dzpdx(i) = ds/dx(xp(i),yp(i),zp(i))
dzpdy(i) = ds/dy(xp(i),yp(i),zp(i))
dzpdz(i) = ds/dz(xp(i),yp(i),zp(i))
The out_mode parameter defines the evaluation rule for extrapolation,
i.e. for (xp(i),yp(i),zp(i)) not in [xmin,xmax]x[ymin,ymax]x[zmin,zmax]:
"by_zero": an extrapolation by zero is done
"by_nan": extrapolation by Nan
"C0": the extrapolation is defined as follows :
s(x,y) = s(proj(x,y)) where proj(x,y) is nearest point
of [x(1),x(nx)]x[y(1),y(ny)] from (x,y)
"periodic": s is extended by periodicity.
Examples
// see the examples of the splin3d help page
See Also
splin3d, bsplin3val,
Authors
-
R.F. Boisvert, C. De Boor (code from the CMLIB fortran lib)
-
B. Pincon (scilab interface)